See the best of londons royal highlights on a 4 hour walking tour begin with an early access visit to the infamous tower of london where youll see the opening ceremony and be dazzled by the crown jewels then soak up the sights during a 30 minute thames river cruise before taking in the changing of the guard at buckingham palace or horse guards parade end your tour outside the palace where youll learn about queen elizabeth ii and the history of the british royal family